#silverlightControlHost {
height: 200px;
width: 300px;
left:50%;
top:50%;
margin-left:-150px;
margin-top:-100px;
position: absolute;
text-align: center;
}
根据需要修改
的值即可
height: 200px;
width: 300px;
和
margin-left:-150px;
margin-top:-100px;